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Prairies and savannas are both grasslands, but prairies have fewer trees. Savannas feature scattered trees, often oaks. These habitats often blend together. Illinois' prairies formed after glaciers shaped the land, with tallgrass prairies once covering much of the state. Rich prairie soil led to most prairies being converted to farmland. Today, few native prairies remain. Globally, grasslands make up 20 to 40% of Earth’s land and are called a few different names.

Muskrats are social aquatic rodents often mistaken for beavers or otters. They have long, scaly tails that act as rudders, webbed feet, and waterproof fur. Smaller than beavers, they build lodges or burrows near water and can swim up to 3 mph. Male muskrats use a musky odor from their scent glands to communicate and to warn intruders. They splash their tails to warn of danger and have adapted to live in the water. Muskrats are omnivores and prefer marshes and wetland habitats

Northern short-tailed shrews are secretive, underground insectivores often mistaken for mice, though they aren’t rodents. They have poor vision and use echolocation to navigate. Surprisingly, they are the only venomous mammal in the U.S.—their saliva can paralyze or kill prey. They feed mostly on invertebrates but also eat small animals and some plants.

Scales protect animals, but they vary by species. Reptile and bird scales are keratin-based and form a continuous layer. Fish scales, made of dentin and enamel, are made up of individual scales and come in four types: placoid, cosmoid, ganoid, and elasmoid. Each of these scales can help scientists determine valuable information such as a fish’s age and illnesses. Scale size and type affect locomotion and protection. You can view live examples at Four Rivers' large fish tank.

The world is home to 40 wildcat species, but only one, the bobcat, lives in Illinois. They are more prevalent in the southern part of the state. Bobcats prefer forested areas with a dense understory that are near open areas where they can hunt. A bobcat’s fur’s color helps them blend in with their habitat. They can look similar to domesticated cats and are commonly mistaken for lynx. Bobcats can run up to 30 mph during short sprints and are great stalkers. They often live sol

Boreal chorus frogs are one of the first signs of spring, often heard calling near ponds as early as February. Males sing to attract mates, and females lay up to 1,500 eggs. These small frogs, only 0.7 to 1.2 inches long, live in shallow, still waters. They are green or tan with three stripes down their backs. With short legs, they can only make small hops on land.

Fox and gray squirrels are common in Illinois and look alike, but fox squirrels have reddish-brown fur and are slightly larger, while gray squirrels have gray backs and white bellies. Gray squirrels prefer dense forests while fox squirrels prefer open woods. Other Illinois squirrels include red squirrels and southern flying squirrels. Black and white squirrels aren’t separate species. They get their unique color from genetic mutations like melanism, leucism, or albinism.

Redspotted sunfish, often called stumpknockers, come from a large family and are small freshwater fish with orange (males) or yellowish-brown spots (females). They prefer calm, plant-filled river backwaters. However, pollution, habitat loss, and invasive species led to their decline in Illinois, making them a state endangered species by 2009. Conservation efforts have helped - over 17,000 have been reintroduced, improving their status to threatened.

Robins are familiar birds with orange breasts, found across the U.S. year-round. Though known for eating worms, they also eat insects and fruit. Males and females look similar, with females slightly paler. They breed early, often having multiple broods. Their cheerful song is a sign of spring, though many robins stay quiet in winter. Named after European robins, they’re common in yards and parks and are part of the thrush family.

Animals don’t care what we call them, but naming helps us understand, appreciate, and protect them. We use different names for different types of animals in the same species - like a doe (female deer) or a kit (young skunk). Learning names makes animals more interesting and can inspire us to care for their habitats. Surprised by any group names? Curious about others? That curiosity is a great reason to learn more!

Robins find worms using sight, not sound, smell or touch. They tilt their heads to look into holes they or others have made, spotting visible worms below the surface. Studies show robins ignore sounds or smells and only react when they can see a worm. Other birds eat worms too, like killdeers and woodcocks. Woodcocks do a unique dance once thought to help find worms, but it may actually be a warning signal to predators.

Many animals are nocturnal, meaning they’re active at night and rest during the day. This behavior helps them avoid predators, reduce competition, hunt more effectively, or stay cool in hot climates. Some species are also becoming more nocturnal to avoid humans. These animals often have special adaptations like sharp hearing, enhanced night vision, or echolocation. However, threats like light pollution and climate change may disrupt their nocturnal habits and ecosystems.

Once endangered in Illinois, river otters now live statewide thanks to conservation efforts. These playful animals are built for swimming but spend much time on land. They dive, slide, and teach pups survival through play. Often confused with sea otters, river otters are smaller and more land-based. They eat fish, frogs, and crayfish to fuel their high metabolism and use their whiskers to detect prey underwater.

Eastern milk snakes, Illinois' official state snake since 2022, are harmless, non-venomous constrictors found in fields, woodlands, or river bottoms. They’re active from April through November, mostly at night, and feed on prey no bigger than them. Farmers once blamed these snakes for their low milk production, accusing them of drinking their cow’s milk, hence their name. They’re shy and pose no threat to humans unless provoked. Look for their blotchy gray and brown “checkere

The American bison, often called a buffalo, is North America’s largest mammal. Males can weigh 2,000 pounds and stand 6 feet tall. The name “buffalo” likely came from the French word “boeuf” for beef. Native tribes had their own names, like tatanka and iinniiwa. Bison once roamed Illinois but now can be seen in places like Midewin National Tallgrass Prairie.

American minks are nocturnal, solitary and semiaquatic carnivores found near waterways across all of Illinois. Often mistaken for beavers or muskrats, they resemble weasels with dark brown fur and a white chin patch. Minks will purr, hiss, and use chemical signals to communicate. They can secrete foul-smelling liquid when scared or excited. They are fast, fierce, and able to swim and climb. Though few predators hunt them, humans remain their biggest threat.

Common goldeneyes are striking ducks with bright yellow eyes, whistling wings, and unique mating dances. They nest in tree cavities, and hatchlings leap 40 feet the day after hatching. They are fast fliers and skilled divers that crave aquatic animals and plants. Seen in Will County lakes during winter, they head north to nest in summer. Spot them at local preserves like Lake Renwick and Rock Run Rookery. Keep an eye out for these amazing waterfowl!

Pileated woodpeckers are the largest in North America, about the size of a crow. With black bodies, white facial stripes, and bright red heads, they’re easy to spot. They live in mature forests and peck rectangular holes in trees to find carpenter ants. Their loud drilling can be heard from afar, and the holes they leave behind often become homes for smaller birds.

Most animals hunt for food day by day. However, some animals, like squirrels and chipmunks, hoard and bury their supply of food while others, like chickadees and nuthatches, hide their food under loose bark, chimneys, and sides of buildings. Animals who eat live prey will dig underground chambers filled with their food source, like moles, or will hide their leftovers with surrounding scraps of terrain, like bobcats and foxes.

Red squirrels live in northeastern Illinois and are smaller and less common than fox or gray squirrels. They are 10 to 15 inches long with orangish-red fur, white bellies and a white ring around their eyes. Their tails are shorter and less bushy. Red squirrels eat seeds, nuts and plant matter and prefer forests with pine trees, though they also live in deciduous forests.